Some keys on the keyboard are not working

I have a strange phenomenon:
I installed Opensuse 13.1 on an ASUS UX31A. After installation, the keyboard was working well. After installing all online updates, some letters/keys on the keyboard did not work any more, e.g. "d" "f" "del" "enter".
I'am writting this question from a second ASUS UX31A, installed some weeks ago. Here, everything is working fine. The language schema (germany), keyboard type (Generic, 101 keys) is the same.

Does somebody has an idea, how I can use all keys on the keyboard?

Michael